Method and device for producing a packaged unit

ABSTRACT

A packaged unit includes a cluster of products and a shrink film that secures the products to each other. The shrink film is wrapped around the cluster, thereby forming a lateral opening that would otherwise result in a shrink eye. A closure formed by placing a portion of the shrink film against the cluster at in the region of the lateral opening forms a closed surface with overlapping fold regions of the shrink film, thus avoiding the shrink eye.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage of International Application No.PCT/EP2009/007254, filed on Oct. 8, 2009, which claims the benefit ofthe priority date of German Patent Application No. 102008052633.9, filedon Oct. 22, 2008. The contents of both applications are herebyincorporated by reference in their entirety.

FIELD OF DISCLOSURE

The invention relates to shrink-wrapping a product cluster, and inparticular, to eliminating the shrink eye in such shrink wrapping.

BACKGROUND

A method and an associated device for forming shrink packaging are knownfrom DE 10 2006 036 590 A1. In this case, to form a group, the shrinkfilm is wrapped around a group unit such that each group is surroundedat the top and at the bottom. On two oppositely situated sides theshrink film does not abut against the group, but rather protrudes fromthe group and consequently forms openings through which hot air passesinto the group during the subsequent shrinking process. The size of theshrink film is reduced through the effect of hot air and/or heat on theshrink film.

Reducing the size of the shrink film causes it to abut tightly againstthe product group, thus causing to to be secured. However, shrink eyesemain as openings on the lateral faces. Because of these shrink eyes,the shrink wrap fails to completely protect the individual products ofthe finished package against unauthorized access.

The shrink eyes also have a negative effect of the stability of thepackaging. To improve stability of a shrink-wrapped packaged unit, manypackers insert stabilizers prior to shrink-wrapping. Examples of suchstabilizers include cardboard bottoms, pads, or trays onto which theproducts are deposited and form the product cluster. Once the packagedunit assembled in this manner has been wrapped around with the shrinkfilm, the necessary stability is achieved.

However, the depositing of the products onto a stabilizer requires anadditional processing step. Additionally, the stabilizer must besupplied, which increases packaging costs that are ultimately passed onto a consumer. Finally, the stabilizer must be disposed of.

SUMMARY

The technical problem underlying the invention is to develop a methodand a device for preparing a package for shrink-wrapping in a way thatreduces or eliminates the shrink eye.

This invention solves the above problem by placing the shrink filmagainst the product cluster at least in a region of lateral facesthereof, where prior art methods would create a shrink eye, to form aclosure surface in the form of a closure with, where applicable,overlapping fold regions.

According to the invention, the shrink packaging or the cut of theshrink film is dimensioned such that it forms lateral protrusions beyondthe product cluster. The protrusions are placed against the productclusters in the region of associated lateral faces. This means that thelateral protrusions are capable of generating a closed surface of theshrink film at the lateral faces of the product cluster such that thelateral faces that were formerly left at least partially open areclosed. The method thus avoids shrink eye.

The lateral protrusions of the shrink film are placed against thesurface of the product cluster at least on the region where a shrink eyewould have been formed by earlier methods. The laterial protrusionsdisposed thereon form a closed surface. The shrink film can also beplaced against other surfaces of the product cluster.

In some practices, placing the shrink film against the product clusteris carried out in a contactless manner, without using additionalmanipulation units. One way to do this is to electrostatically chargethe shrink film. Such electrostatic charging is not difficult becausethe shrink film is advantageously a plastic shrink film, such aspolyethylene. These types of plastic material films can easily becharged electrostatically, as described, in an exemplary andnon-restricting manner, in DE 10 2005 024 380 A1 or also DE 101 44 287A1, the contents of which are herein expressly incorporated byreference.

An electrostatically charged shrink film can easily be applied in acontactless manner, without the use of additional manipulation units, tothe lateral faces of the product cluster in the region where the shrinkeyes would have been had known methods been used. This secures theshrink film to this region.

As an alternative to the described contactless securing of the lateralprotrusions to the lateral faces in the region of the opening, it isalso possible to carry out the placement using one or more manipulationunits that actually contact the film. Examples of manipulation unitsinclude guiding means, guide rods, run-up elements, and brushes. Usingthese manipulation units, the lateral protrusions of the shrink film canbe placed against the product cluster with applicable overlapping foldregions.

The appearance of the shrink packaging can be improved in someapplications when measures are taken to reliably prevent the finishedand positioned shrink films from pushing or sliding together or pushingor sliding in relation to the product cluster.

It is also possible to select the electrostatic charging such that theobtainable adhesive strength between the overlapping shrink film orbetween the shrink film and the associated product cluster or therespective surrounding area reliably prevents undesired displacement ofthe shrink film.

In another embodiment or practice of the invention, the shrink film issecured by bonding together the overlapping regions and/or theoverlapping fold regions of the shrink film. In some embodiments orpractices of the invention, this is carried out by providing an adhesivecoating on the shrink film. The adhesive coating is preferably appliedin the region of the lateral protrusions from prior to wrapping or isapplied once the product cluster has been wrapped. Another way to bondthe shrink film by application of adhesive is to apply the adhesive ontothe shrink film by injecting or spraying the adhesive.

In other embodiments or practices of the invention, the fold regions canbe fused by the shrinking operation itself.

In some embodiments and practices of the invention, the shrink film issecured against the product cluster at least in the region of thelateral faces of the product cluster. This means that the lateralprotrusions in the region of the lateral faces are not only activelyplaced against the product cluster but are additionally secured to theproduct cluster. Different types of securement can be used for thispurpose.

In either case, whether adhesive or fusing is used, moving the lateralprotrusions towards the lateral faces to be closed forms the overlappingfold regions. The adhesive present or introduced in the overlappingregion or the action of fusing ensures that the individual folds can nolonger be separated from each other.

A subsequent shrinking operation, for example in a shrink tunnel thatuses hot air or heat radiation, contracts the shrink wrap, therebyeliminating any creases or waves in the shrink film. As a result, theshrink wrap fixedly surrounds the product cluster to form a group. Theshrink eyes that were common on lateral faces of the product cluster aretherefore no longer created. This means that the product cluster istotally encased and completely closed by the film. This means that thestability of a packaged unit is comparable to that obtained in the priorart with the combination of shrink eyes and stabilizers. The method andapparatus described herein thus eliminates the shrink eyes and the needfor additional stabilizers or packaging reinforcement measures.

The method and apparatus of the invention thus eliminates or greatlyreduces the need for reinforcing cardboard bottoms, introduced cardboardstrips, and other stabilizers. Where these stabilizers are not renderedtotally unnecessary, the required dimensions of these stabilizers arereduced, thus resulting in a cost saving.

The packaged unit produced according to the inventive method and usingthe inventive apparatus comprises the product cluster and thesurrounding shrink film encasing it without any additionalreinforcement. The stability of this packaged unit makes it easy tostore or to transport. Any manipulation of the products when theproducts are displayed, for example, in a shop is almost completelyprevented.

In some embodiments, the shrink film is wrapped around the productcluster with overlapping edges and is subsequently shrunk on. In many ofthese embodiments, the overlapping regions are the longitudinal edgesbecause the shrink film is wrapped around the product cluster in itslongitudinal direction. As a result, prior art methods would have leftshrink eyes in the transverse direction of the product cluster. Theseshrink eyes are not present according to the invention.

One way to avoid shrink eyes is to have a pair of narrow side folds anda pair of broad side folds, both of which result from the lateralprotrusions of the shrink film beyond the lateral faces. The narrow sidefolds are produced by placing the lateral protrusions of the shrink filmwrapped around the product cluster on the narrow sides of the productcluster against those narrow sides. The broad side folds are produced byhaving the lateral protrusions on the wide sides of the product clusterbe subjected to a similar placing operation. In some embodiments,suitable manipulation units place the associated narrow side protrusionsand wide side protrusions against the associated side faces of theproduct cluster. Suitable manipulation units include guiding means,guide rods, run-on elements, and brushes.

When the manipulating unit is a brush, it is useful to provide arotating brush and/or to mount the brush on a pivot arm that moves thebrush.

As a rule, the broad side protrusions and the narrow side protrusions orthe associated wide side folds are secured together to the narrow sidefolds. Associated and overlapping fold regions can be bonded together.However, the bonding step can be rendered unnecessary by instead usingthe shrinking operation to fuse the regions together.

In order to obtain this in detail, the narrow side folds are made beforemaking the broad side folds. For this purpose, associated manipulationunits or brushes initially place the narrow side protrusions against thecorresponding lateral faces. The is followed by similar placement of thewide side protrusions or associated wide side folds.

It is preferable for the product cluster to be initially wrapped looselyby the shrink film, with the shrink film overlapping advantageously atits edges. Preferably, the shrink film overlaps at a longitudinal edge.In this way, during the subsequent shrinking operation, the shrink filmavoids exposing any region of the product cluster. This results in aproduct that is encased over its entire surface.

In one aspect, the invention features an apparatus for producing apackaged unit. Such an apparatus includes a separating device, ashrinking device, and a manipulation unit. The separating deviceseparates out individual products from a product stream and combinesthem to form a product cluster. The shrinking device secures the productcluster on all sides by applying a shrink film, wherein the shrink filmis wrapped around the product cluster thereby forming at least onelateral opening before being shrunk on. The manipulation unit places theshrink film against the product cluster at least in the region of thelateral opening thereby forming a closed surface in the form of aclosure with, where applicable, overlapping fold regions.

In some embodiments, the manipulation unit comprises a bonding devicefor placing the film in position in a contactless manner.

In other embodiments, the manipulation unit comprises at least one brushadapted to place laterally protruding ends of the shrink film againstthe product cluster in the region of the lateral opening with, whereapplicable, overlapping fold regions. Among these are embodiments thatinclude three additional brushes, thereby providing a total of fourbrushes, each of which is assigned to operate on a corresponding lateralface of the product cluster.

In embodiments that have a brush, there can be a pivoting arm forrotating and moving the brush.

In yet other embodiments, the manipulation unit comprises anelectrostatic charging unit for placing the shrink film in position in acontactless manner.

In another aspect the invention features an apparatus for receivingindividual products that have been combined into a product cluster thathas been loosely wrapped by shrink film in a way that forms at least onelateral opening. Such an apparatus includes a manipulation unitstructured and configured for producing a packaged unit from the productcluster. The manipulation unit is configured to place the shrink filmagainst the product cluster at least in a region of the lateral opening.Placement of the shrink film against the product cluster forms a closedsurface thereon. After placement, the shrink film is shrunken on.

In some embodiments, the manipulation unit is structured and configuredfor bonding the film into position in a contactless manner.

In other embodiments, the apparatus also includes a brush adapted toplace laterally protruding ends of the shrink film against the productcluster in the region of the lateral opening. Among these areembodiments in which the manipulation unit includes four brushes, eachof which is assigned to operate on a corresponding lateral face of theproduct cluster.

In yet other embodiments, the manipulation unit includes a brush and apivot arm. The brush is adapted to place laterally protruding ends ofthe shrink film against the product cluster in the region of the lateralopening. The pivot arm is configured for moving the brush. Among theseembodiments are those in which the pivot arm is configured for movingthe brush by rotating the brush about an axis defined by the pivot arm.

In yet other embodiments, the manipulation unit includes N brushes and Npivot arms and n is an integer between 1 and N inclusive. The n^(th)pivot arm is configured to operate on an n^(th) lateral face of theproduct cluster and also to move the n^(th) brush. In a preferredembodiment, N=4.

In yet other embodiments, the manipulation unit includes N brushes and Npivot arms and n is an integer between 1 and N inclusive. The n^(th)pivot arm is configured to operate on an n^(th) lateral face of theproduct cluster and also to rotate the n^(th) brush. In a preferredembodiment, N=4.

In additional embodiments, the manipulation unit is configured forelectrostatic charging of the shrink film, thereby enabling placement ofthe shrink film in position in a contactless manner.

Also included are embodiments in which the manipulation unit includes abrush adapted to place laterally protruding ends of the shrink filmagainst the product cluster in a region of the lateral opening withoverlapping fold regions.

In yet another aspect, the invention features an apparatus for preparinga product cluster for shrink-wrapping. Such an apparatus includes amanipulation unit structured and configured for producing a packagedunit from the product cluster. The manipulation unit includes means forclosing a lateral opening of shrink film on a product cluster that hasbeen loosely wrapped with shrink film in such a way as to leave thelateral opening in the shrink film.

Among the embodiments are those in which the manipulation unit includesmeans for placing laterally protruding ends of the shrink film againstthe product cluster in the region of the lateral opening, and those inwhich the manipulation unit includes means for placing laterallymultiple sets of protruding ends of the shrink film againstcorresponding multiple regions of the product clusters, wherein themultiple regions correspond to multiple lateral openings.

Yet other embodiments include those in which the manipulation unitincludes means for placing laterally protruding ends of the shrink filmagainst the product cluster in the region of the lateral opening, andmeans for moving the means for placing the laterally protruding ends.Among these are embodiments in which the means for placing the laterallyprotruding ends includes means for rotating the means for placing thelaterally protruding ends.

BRIEF DESCRIPTION OF THE FIGURES

These and other features of the invention will be apparent from thefollowing detailed description and the accompanying claims, in which:

FIG. 1 shows a packaged unit,

FIG. 2 shows an apparatus for preparing the package unit of FIG. 1 forshrink wrapping, and

FIG. 3 shows a finished packaged.

DETAILED DESCRIPTION

FIG. 1 shows a packaged unit that comprises a shrink film 1 and aproduct cluster 2 that is encased by the shrink film 1. The productcluster 2 is formed from individual products 3 that are best seen inFIG. 3.

In the exemplary embodiment, the products 3 are cans. These cans can bebeverage cans. Alternatively, the cans are rotationally symmetric andcylindrical containers. The containers can accommodate beverages, aswell as foodstuffs. The products 3 are combined to form a packaged unitin the manner described below.

The products 3 are initially separated from a product stream by aseparating device, which is conventional and therefore need not beshown. The products 3 are then combined to form the product cluster 2.During this process, they are aligned and compacted to the extent wherethey abut against each other. A shrink film 1 then secures the products3 or the product cluster 2 so that packaged units that have beenproduced in this manner can be better stored and/or conveyed.

Initially, the shrink film 1 is loosely wrapped around the productcluster 2, as is shown in FIG. 1. Loosely wrapping the shrink film canbe carried out by a winding machine, which is conventional and thereforeneed not be shown. In the case of this operation, the shrink film 1 iswrapped around the product cluster 2 such that respective edges 1 a, 1 boverlap, as can be seen in FIG. 1. In the exemplary embodiment the edges1 a, 1 b are longitudinal edges 1 a, 1 b of the shrink film 1. Howeverthis configuration is only an example and is not limiting.

In the illustrated embodiment, the shrink film 1 is wrapped around theproduct cluster 2 in the longitudinal direction L such that the lateralfaces 2 a face the direction L. However, this is not mandatory.

A packaged unit formed in this manner has lateral protrusions 4 a, 4 bthat protrude beyond an associated lateral face 2 a of the productcluster. In this case, the lateral protrusions 4 a, 4 b of the shrinkfilm 1 are dimensioned such that the shrink film 1 closes the lateralface 2 a when the lateral protrusions 4 a, 4 b are placed against thelateral face 2 a or the product cluster 2.

The shrink film 1 is initially wrapped in a hose-shaped manner aroundthe product cluster 2, as shown in FIG. 1. When wrapped, the shrink film1 forms an opening 5 that exposes the two lateral faces 2 a. The opening5 has only one closure 6, which is seen in FIG. 2.

The closure 6 is defined such that the shrink film 1 or its lateralprotrusions 4 a, 4 b can be placed against the product cluster 2 in theregion of the opening 5 thereby forming a closed surface. For thispurpose, along with the aformentioned separating device and aconventional shrinking device placed at the end of the production pathfor the final mutual securing of the products 3 by way of the shrinkfilm 1, an apparatus for producing a packaged unit has a plurality ofmanipulation elements 7, which are shown in FIG. 2, for producing thepackaged unit shown in FIG. 3.

Each manipulation unit 7 has at least one brush 7 a that is supported bya pivot arm 7 b. In some embodiments, the brush 7 a rotates about anaxis defined by the pivot arm 7 b. However, there are embodiments wherethis is not the case.

Using the brush 7 a or the manipulation units 7, the lateral protrusions4 a, 4 b of the shrink film 1 are placed against the product cluster 2in the region of the opening 5. At the same time, overlapping foldregions 8 a, 8 b, as shown in FIG. 2, are formed. In one embodiment,there are four brushes 7 a. This configuration is useful forblock-shaped product clusters since there will then be one brush 7 a perlateral face of the product cluster 2.

The lateral protrusions 4 a, 4 b include narrow side protrusions 4 a andbroad side protrusions 4 b. The broad side protrusions 4 b are placedagainst the lateral faces 2 a by associated manipulation units 7 on thecorresponding broad sides of the block-shaped product cluster 2. Thefold regions 8 b according to FIG. 2 in the exemplary embodiment areformed in this way.

The fold regions 8 b corresponding to FIG. 2 may be secured or becomesecured to the lateral face 2 a by the shrink film 1 having beencompletely charged electrostatically beforehand and the manipulationunits 7 being responsible for moving the associated lateral protrusionsnearer until they are attracted by the electrostatically charged lateralface 2 a. As an alternative or in addition to this, it is also possiblefor the fold regions 8 b to be bonded together, or bonded to the productcluster 2. The same is also true for the narrow protrusions 4 a and theresultant fold regions 8 a.

In each case, the placing of the narrow side protrusions 4 a is carriedout first such that initially the two associated narrow side folds 8 aare placed against the lateral face 2 a to be covered. The two broadside protrusions 4 b are then placed against the lateral face 2 a andthere form the broad side folds 8 b. In the case of this operation, thebroad side folds 8 b are connected to the narrow side folds 8 a. Thiscan be effected by having a conventional electrostatic unit carry outelectrostatic charging of the shrink film 1 in its entirety or at leastof the lateral protrusions 4 a, 4 b and/or by bonding the fold regions 8a, 8 b.

After the described operations, the packaged unit corresponding to FIG.2 is moved into a shrink tunnel or a comparable shrinking device inwhich the shrink film 1 is shrunken onto the product cluster 2. At thesame time, the products are secured to each other because the size ofthe shrink film 1 is reduced during this operation.

As a result, the lateral faces that were formerly open due to the shrinkeyes are covered by a closed surface through the interaction of thenarrow side folds 8 a and broad side folds 8 b. The disclosed apparatusand its method of operation thus close the shrink eyes. The shrink film1 therefore completely encases the product cluster 2 after theshrinking-on operation. As a result there is no express need to attachadditional stabilizing elements such as, for example, cardboard covers,etc. This reduces the production costs and the expenditure.

As already represented, in the case of many other applications whereadditional stabilizing elements cannot be dispensed with entirely, thedimensions of the stabilizing elements can be reduced, for example thematerial thickness can be reduced, thereby producing a cost saving evenin such applications.

The electrostatic charging of the shrink film 1 including at least thelateral protrusions 4 a, 4 b can be performed before, during, or afterthe described folding operation. This means that the narrow side folds 8a and broad side folds 8 b can be electrostatically charged after theirproduction as in FIG. 2 to prevent them coming unfolded again. In eachcase, the shrink film 1 remains in its position after the describedoperations, also, in particular in the region of the closure 6, and isalso not displaced by a possible hot air fan in the interior of theshrink tunnel. This means that it is possible for the shrink film 1 tosurround the product cluster without any gaps and, in particular, toalso obtain a reliable closure 6 for the lateral faces that wereformerly open.

Having described the invention, and a preferred embodiment thereof, whatis claimed as new, and secured by letters patent is:

1. A manufacture comprising a packaged unit, said packaged unitcomprising a cluster of products and a shrink film, wherein said shrinkfilm comprises a closure, wherein said shrink film secures said productsto each other, wherein said shrink film is wrapped around said clusterthereby forming at least one lateral opening, wherein said closure is aresult of placing a portion of said shrink film against said cluster atin a region of said lateral opening thereby forming a closed surfacewith overlapping fold regions of said shrink film.
 2. The manufacture ofclaim 1, wherein said closure comprises two narrow side folds and twobroad side folds, wherein said broad side folds cover said two narrowside folds to form said overlapping fold regions.
 3. The manufacture ofclaim 1, wherein said closure comprises two narrow side folds and twobroad side folds, wherein said broad side folds that are securedtogether to said narrow side folds, and wherein said broad side foldscover said narrow side folds to form said overlapping fold regions. 4.The manufacture of claim 1, wherein said closure comprises two narrowside folds and two broad side folds, wherein said broad side folds coversaid narrow side folds to form said overlapping fold regions, andwherein said overlapping fold regions are bonded together.
 5. Themanufacture of claim 1, wherein said closure comprises two narrow sidefolds and two broad side folds, wherein said broad side folds cover saidnarrow side folds to form said overlapping fold regions, wherein saidnarrow side folds are produced before said broad side folds.
 6. Themanufacture of claim 1, wherein said shrink film wrapped around saidproduct cluster overlaps at its edges.
 7. The manufacture of claim 1,wherein said products are containers that are standing upright on basesthereof on directly said shrink wrap.
 8. The manufacture of claim 1,wherein said products are cans that are standing upright on basesthereof on directly said shrink wrap.
 9. The manufacture of claim 1,wherein said packaged unit lacks a shrink eye.
 10. The manufacture ofclaim 1, wherein said packaged unit omits additional stabilizers andpackaging-reinforcement measures.
 11. The manufacture of claim 1,wherein said closure comprises two narrow side folds and two broad sidefolds, wherein said broad side folds cover said narrow side folds toform said overlapping fold regions, and wherein said overlapping foldregions are electrostatically bonded together.